The present invention relates to a tool useful for effecting removal of a push rod from an internal combustion engine.
Typically, multiple stroke, internal combustion engines include push rods which are mechanically linked to valves that open and close ports to the cylinders of the engine. Most often, one end of each push rod is reciprocally driven in response to actuation by a rotating cam. The opposite end of each push rod typically engages one end of a rocker arm which is pivotally biased by a valve spring causing the opposite end of the rocker arm to engage with the push rod. Thus, as the cam rotates, the push rod reciprocates causing the rocker arm to pivot against the biasing force of a valve spring assembly and thereby open or enable closure of a valve port of the internal combustion engine.
A repair operation often necessary with respect to internal combustion engines is replacement of the intake manifold gasket which, in turn, may require removal of the intake manifold. On some engines the push rods must also be removed to allow the gasket surfaces to be cleaned prior to installation of a new gasket. Removal of push rods from an internal combustion engine, however, is not a straightforward mechanical operation. Various means must be employed in order to move the rocker arm out of engagement with the push rod so that the push rod may be effectively removed and replaced. Factors which complicate replacement may include the time and effort to remove parts of the engine in order to secure adequate access to the push rods. An effective, efficient and simple means for removal of push rods thus is an objective long sought by engine mechanics.
U.S. Pat. No. 7,409,755 entitled “Push Rod Removal Tool” issued Aug. 12, 2008, incorporated herein by reference, describes a tool designed to facilitate removal of push rods. The tool performs well in many circumstances. However, changes in engine design may inhibit the effective use of the described tool in some situations. Specifically, the described tool may be too bulky or may have a configuration which may preclude effective use in constricted spaces. This problem arises, for example, in General Motors 3.5L and 3.9L engines. Thus, there is a need for a tool which will enable efficient repair of such engines and in other similar circumstances involving space constraints.